1. Field of the Invention
The present invention relates to a color image processing device, and particularly to simplification of a configuration for carrying out a color adjustment of brightness, contrast, hue and saturation by a manual instruction.
2. Description of the Related Art
As a color image processing device, for example, a copy machine, a scanner, a printer, a facsimile machine and a multifunction peripheral having a combination of these machines are conventionally known. Such a conventional color image processing device generates Red, Green and Blue (RGB) data by using a scanner function.
With respect to a color adjustment of an image processing device, brightness, contrast, hue and saturation are items which can be adjusted easily by a human sense. On the contrary, a desired adjustment is difficult to be carried out for a color space of primary colors such as RGB and Cyan, Magenta and Yellow (CMY). A conventional color image processing device adjusts scanned colors after converting RGB data into Lab data (uniform color space data).
In a conventional color image processing device, a luminance color difference signal is input, a correction level of the color difference signal is instructed manually and by using conversion data corresponding to each of the color difference signals, a shift amount relating to each of the color difference signals is determined. The conventional color image processing device includes a correction unit for carrying out a correction process in accordance with the determined shift amount. The correction process is carried out in accordance with the shift amount relating to each of two digital color signals. However, this correction process only shifts the color difference signals for correcting a color temperature, and hue and saturation cannot be adjusted. In addition, brightness and contrast cannot be changed. Furthermore, it is necessary to store the conversion data for all of the color difference signals and a configuration results in being complicated.
As described above, the conventional color image processing device includes a function for converting the RGB data into the Lab data. The adjustment of the scanned colors is executed on the Lab data. In case of compressing and encoding data by a Joint Photographic Experts Group (JPEG) method, a function for converting the RGB data into YCC data (luminance color difference signal) is added to the color image processing device. In this case, to provide a color adjusting function of the YCC data, in addition to a color adjusting circuit of the Lab data, a color adjusting circuit of the YCC data becomes necessary and the configuration results in being complicated.
For example, a multifunction peripheral is required to output image data under three formats when printing out, when carrying out a facsimile transmission and when outputting as image data by using a scanner or the like. A color space which is appropriate or which is to be used in each of the formats has been decided. However, since the conventional color image processing device carries out an adjustment of the scanned colors on the Lab data, only one color adjusting circuit is provided. To carry out a color adjustment of the YCC data, it is necessary to add a circuit.